1. Field of the Invention
The present invention is directed to a brake lining wear sensor and is more particularly directed to a modular progressive brake lining wear sensor.
2. Summary of the Prior Art
Various brake lining wear detection systems are known in the art. In addition, temperature measurement systems are known. One such temperature and wear detection technique monitors the resistance of a temperature sensitive resistor yielding a signal which represents the operating temperature of the brake lining so that extreme temperature conditions can be detected and corrective action taken. Once the electrical conductive loop is worn away, an open circuit is detected which signals the need for lining replacement.
One method to detect brake lining employs an embedded conductive wire loop within the brake lining. When the loop is broken and furthermore, when electrical contact is made between the wire loop and a brake drum surface, lining wear out is detected. Another brake wear and temperature measurement system utilizes a plurality of thermo-responsive elements disposed within the brake lining where each element is selectively monitored to determine if abnormal temperatures have been encountered and/or whether the brake lining has worn to such an extent that one or more of the thermally responsive elements have been broken.
It is an object of the present invention to provide a simple progressive break wear sensor in a single compact erodable element.
The present invention is directed to a modular progressive brake lining wear sensor. A sensor has a triangular wedged shaped resistive member disposed between a pair of conductive plates to define a triangular shaped sensor. The sensor is disposed within an erodable molding and connected to a sensing circuit. A pair of leads are connected one each to a ground lead and a resistive lead which in turn are connected to a closed sensing circuit. The ground lead and resistance lead emerge from the encapsulated sensor for connection to the sensing circuit. The sensor is disposed within the brake lining and is connected to the brake shoe. As the brake lining progressively wears, the triangular wedged shaped resistive member is progressively worn away thus continuously changing the overall resistance of the sensor. The change in resistance provides for continuous indication of the state of wear of the brake lining.